JP2013220406A - Apparatus for treating cleaning wastewater, and method for treating cleaning wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for treating cleaning wastewater in which the condensation of organic substances in the apparatus for treating wastewater are suppressed at a low cost, and the recovery rate of wastewater is high.SOLUTION: An apparatus 1 for treating cleaning wastewater which treats cleaning wastewater containing organic acids and organic substances drained from a cleaning device 34 in a water usage device 32 having a plurality of devices which use desalination water obtained by desalinating raw water by a desalination device 30 includes: a reduction device 10 for reducing the organic acids in the cleaning water; an ion constituent-removing device 12 for removing ion constituents contained in the reduction-treated water; and a recovered water feeding-pipe 24 for feeding at least one part of the recovered water, which is recovered by ion constituent removal treatment, to a more upstream side than the desalination device 30.

Description

  The present invention relates to a treatment apparatus and a treatment method for washing wastewater, and more particularly, to a treatment apparatus and treatment method for washing wastewater generated when a container such as a PET bottle before filling a beverage product or the like is washed and sterilized.

  In food factories, etc., purified water that has been treated by fine water removal using sand filtration, pressurized flotation, microfiltration, etc., and desalination processes such as RO membrane treatment, etc. using well water, etc. We use in facilities. One of the facilities is a cleaning facility (rinser facility).

  When a product is aseptically filled into a container in a food factory or the like, a disinfectant is usually used to sterilize the container. As a disinfectant, a cleaning liquid in which acetic acid, peracetic acid and hydrogen peroxide are mixed is called oxonia and is widely used. The sterilized container is introduced into a cleaning facility in order to wash away the attached disinfectant. In the cleaning facility, a large amount of water is used to clean and drain the disinfectant adhering to the container. For this reason, in recent years when it is desired to reduce water resources in food factories, etc., many wastewater recovery methods have been proposed in which this wastewater is recovered by a cleaning wastewater treatment device (rinser wastewater treatment device) and reused in a cleaning facility. (For example, see Patent Documents 1 and 2).

  As described in Patent Document 1, hydrogen peroxide and peracetic acid are decomposed into acetic acid using a catalyst such as activated carbon, and then an anion exchange resin is used as a treatment and recovery method for washing waste water (rinser waste water). A typical method is to adsorb acetic acid and reuse the resulting treated water in a washing facility. Moreover, in this process, in order to prevent propagation of various germs in the washing waste water treatment apparatus, sterilization treatment such as hot water sterilization, sterilization using hypochlorous acid, and sterilization using UV may be used in combination.

  On the other hand, when such a cleaning wastewater treatment apparatus is operated, organic substances such as aldehydes may be detected in the cleaning wastewater treatment apparatus. Although the elution or generation mechanism of organic substances such as aldehydes has not been clarified, elution from any step in the washing waste water treatment apparatus or elution from a rinsed product container is assumed. As for aldehydes, formaldehyde is 0.08 mg / L on the basis of tap water quality, and acetaldehyde is listed as an item to be examined (as of January 25, 2011). It is desirable not to exceed the standard.

  In the treatment and recovery of washing wastewater, there is a method that can be used to purify the washing wastewater and supply it as washing water (rinser water). However, organic substances such as aldehydes are eluted or generated from the washing equipment in the washing wastewater treatment equipment. For example, the formaldehyde tap water standard of 0.08 mg / L may be exceeded. Patent Document 3 proposes a method for removing aldehydes from the water to be treated containing aldehydes, but only 2 ppm of formaldehyde in the water to be treated is removed to 1.1 ppm. poor. Therefore, in order to remove a relatively high concentration of aldehydes, a great investment in equipment such as an oxidation treatment facility is required.

JP 2001-129564 A JP 2008-093511 A JP 2010-247909 A

  An object of the present invention is to provide a cleaning wastewater treatment device and a cleaning wastewater treatment method that suppresses the concentration of organic substances in the washing wastewater treatment device at a low cost and has a high wastewater recovery rate.

  The present invention is a treatment apparatus for washing wastewater for treating washing wastewater containing organic acids and organic matter discharged from washing equipment in a water use facility having a plurality of facilities using desalted treated water obtained by desalting raw water. A reduction means for reducing the organic acid in the washing waste water, an ionic component removal means for removing ionic components contained in the reduction treated water treated by the reduction means, and a treatment by the ionic component removal means And a recovered water supply means for supplying at least a part of the recovered water recovered to the upstream side of the desalting process.

  In addition, the present invention is a treatment of washing wastewater that treats washing wastewater containing organic acids and organic matter discharged from washing equipment in a water use facility having a plurality of facilities that use desalted treated water obtained by desalting raw water. A reduction process for reducing the organic acid in the washing waste water, an ionic component removal process for removing ionic components contained in the reduced water treated in the reduction process, and the ionic component removal process And a recovered water supply step of supplying at least a part of the recovered water that has been processed and recovered to the upstream side of the desalting process.

  In the present invention, in the treatment of washing wastewater for treating washing wastewater containing organic acids and organic matter discharged from washing equipment in a water use facility having a plurality of facilities using desalted treated water obtained by desalting raw water, By supplying at least a part of the recovered water recovered by the reduction treatment and the ionic component removal treatment to the upstream side of the desalting treatment, the concentration of organic substances in the washing waste water treatment apparatus is suppressed at a low cost, and A wastewater treatment apparatus and a wastewater treatment method having a high wastewater recovery rate can be provided.

It is a schematic structure figure showing an example of the washing drainage processing device concerning the embodiment of the present invention. It is a schematic block diagram which shows the washing | cleaning waste water treatment apparatus used in the Example. It is a figure which shows the water balance in the Example of this invention. It is a schematic block diagram which shows the filtration apparatus used in the Example.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  The inventors of the present invention examined the amount of organic substances such as aldehydes in the process of the cleaning wastewater treatment apparatus from the cleaning equipment. As a result, organic substances such as aldehydes are hardly detected by only passing through the cleaning wastewater treatment apparatus once from the cleaning facility, and the concentration of organic substances such as aldehydes is proportional to the circulation through the cleaning wastewater treatment apparatus. It was revealed that it rose and eventually exceeded a detectable concentration level. This means that when wastewater is treated and recovered using a cleaning wastewater treatment device and reused as cleaning water, the higher the wastewater recovery rate in the cleaning wastewater treatment device, the higher the concentration of organic substances such as aldehydes. Means high concentration.

  On the other hand, the present inventors have clarified that organic substances such as aldehydes are hardly concentrated in a desalination treatment facility such as an RO facility that desalinates raw water introduced into a cleaning facility or the like. Therefore, in the present embodiment, at least a part of the recovered water recovered by the cleaning wastewater treatment apparatus is sent to the upstream side of the desalination step in the desalination processing facility further upstream than the cleaning facility, thereby the RO membrane. Organic substances such as aldehydes are hardly concentrated in the desalination process such as treatment process, and the concentration of organic substances such as aldehydes is suppressed when the recovered water collected by the washing wastewater treatment equipment is reused as washing water. Therefore, the present invention provides a washing wastewater treatment system and a washing wastewater treatment method that have a high wastewater recovery rate without using expensive incidental facilities. Thereby, concentration of organic substances, such as aldehydes, in the washing waste water treatment apparatus can be suppressed at low cost, and water resources can be saved.

  An outline of an example of a cleaning wastewater treatment apparatus according to an embodiment of the present invention is shown in FIG. The cleaning waste water treatment apparatus 1 includes a reduction device 10 as a reduction unit and an ion component removal device 12 as an ion component removal unit. The cleaning waste water treatment apparatus 1 may include a sterilization device 14 as a sterilization unit, and may include a recovered water storage tank (not shown) in the subsequent stage of the sterilization device 14.

  In the cleaning wastewater treatment apparatus 1 of FIG. 1, the cleaning drainage pipe 16 from the cleaning facility 34 in the water use facility 32 having a plurality of facilities that use water is connected to the inlet of the reduction device 10, and the outlet of the reduction device 10 and the ions The inlet of the component removal device 12 is connected by a reduction treatment water pipe 18, the outlet of the ionic component removal device 12 and the inlet of the sterilization device 14 are connected by an ionic component removal treatment water pipe 20, and the outlet of the sterilization device 14 is The sterilization water pipe 22 is connected to the cleaning water inlet of the cleaning facility 34. The sterilized water pipe 22 is connected to the raw water tank 26 by a recovered water supply pipe 24 as a recovered water supply means for supplying at least a part of the sterilized water to the raw water tank 26 as recovered water. The outlet of the raw water tank 26 and the inlet of the particulate removing device 28 are connected by a raw water pipe 36, and the outlet of the particulate removing device 28 and the inlet of the desalting device 30 are connected by a particulate removing treated water piping 38. Is connected to the water use facility 32 by a desalinized water supply pipe 40 as a desalinized water supply means for supplying at least a part of the desalinized water to the water use facility 32 including the cleaning facility 34. . A drainage pipe 42 for discharging the wastewater is connected to the water use facility 32.

  The cleaning wastewater treatment method and the operation of the cleaning wastewater treatment apparatus 1 according to the present embodiment will be described.

  The raw water used in the water use facility 32 is stored in the raw water tank 26 and then sent to the fine particle removing device 28 through the raw water pipe 36, and the fine particles contained in the raw water are removed in the fine particle removing device 28 (fine particles). Removal step). The fine particle removal treated water from which the fine particles have been removed is sent to the desalination apparatus 30 through the fine particle removal treatment water pipe 38, and is desalted in the desalination apparatus 30 to remove salt and the like contained in the fine particle removal treatment water. (Desalting step). The desalted treated water that has been desalted is supplied to the water use facility 32 through the desalted treated water supply pipe 40, and the desalted treated water is used in a plurality of facilities including the cleaning facility 34 in the water use facility 32. At least a part of the waste water from the water use facility 32 is discharged through the drain pipe 42. The fine particle removal step may be omitted depending on the properties of the raw water.

  Organic acid-containing cleaning water in which an organic acid for cleaning and sterilization is added to desalted water is supplied to the cleaning facility 34. In the cleaning facility 34, for example, containers such as PET bottles before filling of beverage products are cleaned. Sterilized. After washing and sterilization, the organic acid remaining in the container is washed away with washing water. At least a part of the cleaning wastewater (rinser wastewater) containing organic acid and the like generated in the cleaning equipment 34 is sent to the reduction device 10 of the cleaning wastewater treatment device 1 through the cleaning drainage pipe 16 and reduced in the reduction device 10. (Reduction process). The reduced treated water treated by the reducing device 10 is sent to the ionic component removing device 12 through the reduced treated water pipe 18 and the contained ionic components are removed (ionic component removing step). The ionic component removal treated water treated by the ionic component removal device 12 is sent to the sterilizer 14 through the ionic component removal treated water pipe 20 and sterilized (sterilization process). At least a portion of the sterilized water treated by the sterilizer 14 is circulated to the cleaning facility 34 through the sterilized water pipe 22 and reused as the cleaning water. Further, at least a part of the sterilized water is supplied as recovered water to the raw water tank 26 that is upstream of the desalting apparatus 30 through the recovered water supply pipe 24. The recovered water is mixed with the raw water in the raw water tank 26 and reused.

  At least a part of the sterilized water may be supplied to the upstream side of the desalting apparatus 30 as recovered water. In addition to being fed to the raw water tank 26, it is supplied to the raw water pipe 36 and the particulate removal treated water pipe 38. May be.

  In the cleaning facility 34 in a part of the water use facility 32, generally, about 1/10 of the total desalted water used in the water use facility 32 is used. In the cleaning facility 34, for example, the container is sterilized, and then the organic acid remaining in the container is flushed with cleaning water (rincer water). This washing waste water contains organic acids and organic substances. Examples of organic acids include acetic acid and peracetic acid. When oxonia (a mixture of acetic acid, peracetic acid, and hydrogen peroxide) is used as a disinfectant, hydrogen peroxide is included in addition to the organic acid. Also good. As described above, at least a part of the cleaning wastewater containing the organic acid and organic matter generated in the cleaning facility 34 is processed in the cleaning wastewater treatment system 1.

  The recovered water may contain, for example, aldehydes such as formaldehyde and acetaldehyde, alcohols, and organic substances such as organic solvents represented by organic chlorine compounds. When this recovered water is returned to the raw water tank or the like of the cleaning facility 34, there is no mechanism for removing organic substances such as aldehydes in the cleaning facility 34. Therefore, concentration of organic substances such as aldehydes occurs in the system. The water standard of 0.08 mg / L may be exceeded.

  In the present embodiment, it is possible to suppress the concentration of organic substances such as aldehydes in the system by returning all or part of the recovered water to the raw water tank 26 of the entire water use facility 32.

  Organic matter such as aldehydes in the recovered water returned to the raw water tank 26 of the entire water use facility 32 is almost detected by being diluted according to the amount of water used in the cleaning facility 34 with respect to the amount of water used in the water use facility 32. The concentration will decrease to: Even if there is an RO membrane treatment step in the desalting step from the raw water tank 26 through the fine particle removal step, it is rarely unintentionally concentrated in the RO membrane treatment step, etc., as shown in the examples described later. .

  In this way, the water supplied again to the cleaning facility 34 contains almost no organic matter such as aldehydes. On the other hand, almost all of the washing waste water can be recovered as recovered water in the raw water tank 26 of the entire water use facility 32, and the amount of raw water used such as well water, industrial water, and clean water can be reduced accordingly. it can.

  In order to suppress the concentration of organic matter in the cleaning wastewater treatment apparatus, the ratio of the amount of water used in the cleaning facility 34 to the amount of water used in the water using facility 32 is preferably as small as possible. The ratio of the amount of water used in the cleaning facility 34 to the amount of water is preferably about 60% or less, and more preferably 54% or less. Moreover, the ratio of the supply amount of the recovered water to the raw water tank 26 with respect to the amount of treated water (for example, sterilized treated water) treated by the cleaning wastewater treatment apparatus 1 may be determined according to the amount of organic matter in the treated water amount. For example, it may be about 35% or less.

  The reducing device 10 is not particularly limited as long as it can reduce at least an organic acid. Examples of the reducing device 10 include a device filled with activated carbon, a device filled with a catalyst, and the like. From the viewpoint of cost effectiveness, a device filled with activated carbon is preferable.

  The ion component removing device 12 is not particularly limited as long as it removes at least ion components such as acetate ions generated by decomposition of peracetic acid or the like by a reducing device. Examples of the ion component removal device 12 include an ion exchange device filled with an ion exchange resin, a filtration device equipped with an RO membrane, and the ion exchange device filled with an ion exchange resin in terms of water recovery rate. preferable. As the ion exchange resin, a cation exchange resin, an anion exchange resin, a mixed bed of a cation exchange resin and an anion exchange resin, or the like is used.

  The sterilizer 14 is not particularly limited as long as it can sterilize at least. Examples of the sterilization device 14 include a chlorine sterilization device, a hot water sterilization device, and a UV sterilization device, but a UV sterilization device is preferable in terms of continuity, compactness of the device, and no need for additives. Moreover, the further sterilization effect can be improved by stopping the whole equipment and performing hot water sterilization at intervals of 2-3 days.

  The sterilizer 14 may be anything that irradiates ultraviolet rays having a wavelength of at least 254 nm. As an apparatus for irradiating ultraviolet rays, there are an apparatus that emits ultraviolet rays of 185 to 254 nm, an apparatus that emits light by cutting 185 nm, and the like. As the sterilization apparatus 14, for example, a UV oxidation apparatus that includes a UV lamp that emits ultraviolet rays of 185 to 254 nm and has a wavelength of 185 nm cut by a filter may be used.

  The raw water tank 26 of the entire water use facility 32 is supplied with raw water selected from at least one of well water, industrial water, clean water and the like.

  As the fine particle removing device 28, a sand filtration device, a pressure levitation device, a membrane filtration device or the like is mainly used.

  Examples of the desalting apparatus 30 include an RO membrane treatment apparatus and an ion exchange apparatus including an ion exchange resin. The RO membrane is preferably an ultra-low pressure membrane. In addition, when the raw water contains a lot of silica, it may be made alkaline and passed through the RO membrane, or an ion exchange resin tower may be used in combination, or the ion exchange resin alone may be desalted.

  The desalted water that has been desalted is used as bottling water (product manufacturing), washing water, and the like in the water use facility 32. Among them, relatively clean water may be reused after performing membrane treatment or the like as necessary.

  Examples of the water use facility 32 include water use facilities including a cleaning facility for cleaning containers such as PET bottles before filling of beverage products in the beverage industry, and a cleaning facility for sterilizing can products after product filling. .

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Example 1>
The process of the washing waste water treatment equipment was simulated from the washing equipment, and a confirmation test of the amount of aldehydes eluted was conducted. An experimental apparatus diagram is shown in FIG. 2, the outlet of the reducing device 10 and the inlet of the ionic component removing device 12 are connected by a reducing water pipe 18, and the outlet of the ionic component removing device 12 and the inlet of the sterilizing device 14 are connected. Connected by the removal treated water pipe 20, the raw water tank 44 is installed in the preceding stage of the reducing device 10, the outlet of the sterilizer 14 is connected to the raw water tank 44 by the recovered water supply pipe 24, and the outlet of the raw water tank 44 and the reducing device Ten inlets were connected by raw water piping 48. A pump 46 is installed in the raw water pipe 48.

The following devices were used as each device.
Reduction device: Activated carbon filling (1L)
Ion component removal device: mixed bed type of cation and anion exchange resin (cation: 800 mL, anion: 1600 mL)
Sterilizer: UV irradiation device (UV lamp: manufactured by Nippon Electric Co., Ltd., model SGL-500T4U)
The UV lamp emits ultraviolet light having a wavelength of 185 to 254 nm, and has a wavelength of 185 nm cut by a filter. The UV irradiation amount is 50 mJ / cm ² .

[Experimental conditions]
・ Raw water: Pure water (demineralized with ion exchange resin) + Oxonia (Oxonia Active 90 manufactured by Ecolab)
Oxonia concentration: 1,000 mg / L
・ Raw water flow rate: 10L / h
・ Total amount of water held in the device (simulating actual machine size in proportion to raw water flow rate): 10L

  From the experimental conditions, the time required for the retained water in the cleaning wastewater treatment apparatus to circulate the entire apparatus is 1 h. Table 1 shows the results of sampling the collected water at the outlet of the sterilizer for each circulation and analyzing the formaldehyde according to Schedule 19 of the Ministry of Health, Labor and Welfare Notification No. 261.

  From Table 1, it can be seen that the formaldehyde concentration exceeds 0.08 mg / L, which is the quality standard for tap water in the cleaning wastewater treatment apparatus, by continuously recovering and recycling the cleaning wastewater. If the recovery rate (reuse rate) of water in the cleaning facility is 90% in the process from the cleaning facility to the cleaning wastewater treatment device, for example, 1 / (1-0.9) = 10 times in the system. Water will circulate. At this time, it can be seen from Table 1 that the formaldehyde concentration is 0.22 mg / L. In this way, when organic substances such as formaldehyde may elute or form in the system in the process of the cleaning wastewater treatment equipment from the cleaning facility, if the recovery rate of water is increased in the system, it will be concentrated in the system. It turns out that appropriate water quality is difficult to obtain.

  On the other hand, the water quality of one circulation in this experiment was a water quality satisfying the tap water standard with a formaldehyde concentration of 0.01 mg / L. Consider the case where this water is returned to the raw water tank upstream from the desalination treatment upstream of the washing equipment. Assuming that the recovery rate X of the raw water demineralizer (here RO equipment) is 85%, the recovery rate Y of the water discharged from the water using equipment (here RO equipment) is 60%, water usage The water usage rate S of the cleaning equipment in the equipment was 10% of the supply amount. At this time, FIG. 3 shows the water balance when the amount of water flowing from the raw water tank to the raw water desalting apparatus is 1.

(1) In the water balance shown in FIG. 3, when the dilution rate from the cleaning equipment in the raw water tank is calculated, the following equation is obtained.

[1]
X: RO facility recovery rate of raw water Y: Recovery rate by RO facility of water discharged from water usage facility S: Water usage rate of cleaning facility in water usage facility R: Dilution ratio from cleaning facility in raw water tank From [1], in this case, when X = 0.85, Y = 0.60, and S = 0.1 are substituted, R≈5.4.
(2) In the raw water tank, if the concentration of formaldehyde supplied to the cleaning facility is Zmg / L, it is considered that the concentration is 1 / 0.1848 = 5.4 times diluted.
(0.01 + Z) /5.4 [mg / L] ... [2]
(3) Since Equation [2] = Zmg / L, when Z = (0.01 + Z) /5.4 is solved, Z≈0.0023 mg / L.

  From the above, assuming that 0.01 mg / L of formaldehyde is generated in the cleaning wastewater treatment device, when the entire amount of recovered water is returned to the raw water tank, the recovery rate in the cleaning facility is 100%, and the water quality in each facility is shown in Table 2. Calculated as shown.

  From Table 2, according to the present example, by returning the recovered water to the raw water tank of the entire water-using facility, the water quality of the entire facility is kept below the reference value, and almost the total amount of water used in the cleaning facility is It can be seen that it can be collected.

  In FIG. 3, when the RO equipment in the previous stage is changed to an ion exchange resin and the recovery rate is given, the dilution ratio can be obtained by substituting X = 1 into the equation [1]. When the downstream RO equipment is not installed, the dilution factor can be obtained by substituting Y = 0 into the equation [1]. Further, when R <1 in the formula [1], it means that the system is concentrated.

  In FIG. 3, when the elution concentration of formaldehyde is 0.01 mg / L or more, X = 1 is the maximum recovery rate, and Y = 0.85 is the maximum RO membrane recovery rate. If the amount of water used exceeds 54% of the entire water use facility, even if the entire amount is surely returned to the raw water tank, it will exceed the water supply standard value of 0.08 mg / L. Therefore, it is desirable that the water supplied to the cleaning facility is 54% or less of the entire water use facility.

[Concentration of formaldehyde by RO membrane]
Using a filtration device 50 equipped with an RO membrane 52 (ultra-low pressure membrane: made by Organo, OFR-140HJ8) as shown in FIG. 50% of the sample was permeated through the RO membrane at 2 mL / min, and the concentration of aldehydes in the permeate was measured. The results are shown in Table 3.

  Table 3 shows that the RO membrane hardly concentrates formaldehyde.

  DESCRIPTION OF SYMBOLS 1 Washing wastewater treatment apparatus, 10 Reduction | restoration apparatus, 12 Ion component removal apparatus, 14 Sterilization apparatus, 16 Washing drain piping, 18 Reduction processing water piping, 20 Ion component removal processing water piping, 22 Sterilization processing water piping, 24 Recovery water supply piping , 26, 44 Raw water tank, 28 Fine particle removal device, 30 Desalination device, 32 Water use facility, 34 Cleaning facility, 36,48 Raw water piping, 38 Fine particle removal treated water piping, 40 Desalinated treated water supply piping, 42 Drainage piping , 46 pump, 50 filtration device, 52 RO membrane.

Claims (2)

A wastewater treatment apparatus for treating wastewater containing organic acids and organic matter discharged from a washing facility in a water-using facility having a plurality of facilities that use desalted treated water obtained by desalting raw water,
Reducing means for reducing the organic acid in the washing waste water;
Ionic component removal means for removing ionic components contained in the reduced treated water treated by the reduction means;
Recovered water supply means for supplying at least a part of recovered water treated and recovered by the ion component removing means to the upstream side of the desalting treatment;
A cleaning wastewater treatment apparatus comprising: A treatment method for washing wastewater for treating washing wastewater containing organic acids and organic matter discharged from washing equipment in a water-using facility having a plurality of facilities using desalted treated water obtained by desalting raw water,
A reduction step of reducing the organic acid in the washing waste water;
An ionic component removal step of removing an ionic component contained in the reduced treated water treated in the reduction step;
A recovered water supply step of supplying at least a portion of the recovered water that has been processed and recovered in the ion component removing step to the upstream side of the desalting treatment;
A method for treating cleaning wastewater, comprising: